The development of high energy battery systems requires the compatibility of an electrolyte possessing desirable electrochemical properties with highly reactive anode materials, such as lithium, sodium, and the like and the efficient use of high energy density cathode materials. The use of aqueous electrolytes is precluded in these systems since the anode materials are sufficiently active to react with water chemically. It has, therefore, been necessary in order to realize the high energy density obtainable through the use of these highly reactive anodes and high energy density cathodes to turn to the investigation of nonaqueous electrolyte systems and more particularly to nonaqueous organic electrolyte systems. A large number of nonaqueous organic electrolyte solutions is taught in the art as being suitable for a wide variety of cell systems.
Although a large number of known solid cathode materials is suitable for nonaqueous cell systems, there is always a need for new solid cathode materials to help fill the demand created by the large number of battery-powered devices being marketed. For example, the toy industry has recently embarked upon a program of marketing a multiplicity of computerized games some of which are educational in nature. Many of these devices require portable power sources and, therefore, any new cell system would be welcomed.
French Pat. No. 2,381,395 dicloses nonaqueous (organic) cells having cathodes of the formula MY.sub.k X.sub.z where M is a Group IIA, IIB, IVB, VB or VIIB element or a metal from a group including lead and iron, Y is a Group VA element such as bismuth and X is sulfur, selenium or tellurium, with k being 0 or 1 and z being 3 or more.
It is an object of the present invention to provide new solid cathode materials for nonaqueous cell systems.
It is another object of the present invention to provide a new nonaqueous cell system employing new solid cathode materials selected from the group consisting of bismuth iron sulfide and bismuth lead sulfide.
It is another object of the present invention to provide a new nonaqueous cell system employing an active metal anode, an organic electrolyte based on 3-methyl-2-oxazolidone and an active cathode consisting of the reaction product of two moles of bismuth, two moles of iron and five moles of sulfur or the reaction product of two moles of bismuth, two moles of lead and five moles of sulfur.